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A case study of spatial heterogeneity of soil moisture in the loess plateau,western china:A geostatistical approach

International Journal of Sediment Research 2009年第1期24卷 63-73页

作者： BI Huaxing1,2,LI Xiaoyin3,LIU Xin3,GUO Mengxia3,and LI Jun3 1 Prof., College of Soil and Water Conservation, Beijing Forestry University, Beijing 100083, china, Key Laboratory of Soil and Water Conservation and Desertification Combating, Ministry of Education, Beijing 100083, china 2 Researcher, Ji-xian National Ecological Station of china, Beijing 100083, china 3 Graduate student, College of Soil and Water Conservation, Beijing Forestry University, Beijing 100083, china Prof. College of Soil and Water Conservation Beijing Forestry University Beijing 100083 China Key Laboratory of Soil and Water Conservation and Desertification Combating Ministry of Education Beijing 100083 China Researcher Ji-xian National Ecological Station of China Beijing 100083 China Graduate student College of Soil and Water Conservation Beijing Forestry University Beijing 100083 China

Soil moisture distribution shows highly variation both spatially and temporally. This study assesses the spatial heterogeneity of soil moisture on a hill-slope scale in the loess plateau in West china by using a geostatistical approach. Soil moisture was measured by time-domain reflectometry(TDR) in 313 samples. Two kinds of sampling scales were used(2 x 2 m and 20 x 20 m) at two soil layers(0-30 cm and 30-60 cm). The general characteristics of soil moisture were analyzed by a classical statistics method,and the spatial heterogeneity of soil moisture was analyzed using a geostatistical approach. The results showed that the spherical model is the best-fit model to simulate soil moisture on the experimental hill-slope. The parameters of this model indicated that the spatial dependence of soil moisture in the selected hill-slope was moderate. Even the 2 x 2 m sampling scale was too coarse to show the detailed spatial variances of soil moisture in this area. The dependent distance increased from 27.4 m to 494.16 m as the sampling scale became coarse(from 2 x 2 m to 20 x 20 m). A map of soil moisture was generated by using original soil moisture data and interpolated values determined by the Kriging method. The average soil moisture(area weighted) in the different layers of soil was calculated on the basis of this map(10.94% for the 0-30 cm soil layer,11.88% for the 30-60 cm soil layer). This average soil moisture is lower than the corresponding average effective soil moisture,which suggests that the soil moisture is not sufficient to support vegetation in this area.

关键词： Spatial heterogeneity Soil moisture Geostatistics loess plateau of china

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Effects of precipitation and landuse on runoff during the past 50 years in a typical watershed in the loess plateau, china

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International Journal of Sediment Research 2009年第3期24卷 352-364页

作者： Huaxing BI1, Bin LIU2, Jie WU3, Lei YUN3, Zhihan CHEN2 and Zhewei CUI31 Prof. in hydrology, College of soil and water conservation, Box 67, Beijing Forestry University, 35 Qinghua East Road, Haidian District, Beijing 100083, china, 2 Researcher in hydrology, Xifeng station of soil and water conservation, Xifeng, Gansu Province, china 3 Graduate Assis., College of soil and water conservation, Beijing Forestry University, Beijing 100083, china Prof. in hydrology College of soil and water conservation Box 67 Beijing Forestry University 35 Qinghua East Road Haidian District Beijing 100083 China Researcher in hydrology Xifeng station of soil and water conservation Xifeng Gansu Province China Graduate Assis. College of soil and water conservation Beijing Forestry University Beijing 100083 China

In the past century, great progress has been made worldwide in our understanding of forest-water relationship. The successful forestation programs implemented in china-which have improved the ecological environmental conditions-have gained the attention of many researchers and highlighted the relationship between forestation and water yields. The arid and semi-arid loess plateau has received attention from water engineers and eco-hydrological researchers in china because of a shortage in water resources. We selected one of the oldest stations conducting soil and water conservation experiments, the Xifeng soil and water conservation station, and chose the Nanxiaohe catchment and its paired catchments (Yangjiagou catchment and Dongzhuanggou catchment) as our research areas. Trends in precipitation, air temperature, streamflow over the past 50 years, and the effect of changing land use on streamflow were analyzed. The Mann-Kendall test showed that precipitation had a negative trend (downward trend), whereas air temperature showed a positive trend (upward trend) from the past to present in the Nanxiaohe catchment. However, the trends seen in precipitation, air temperature did not contain any "jumping points." The paired catchment approach is used to detect the effects of land cover change on hydrology in the Yangjiagou and the contrast catchment, i.e., Dongzhuanggou catchment in our study. The results showed a large change in land use in the Yangjiagou catchment from 1954 to 2008. An increase in forested land (from 0% to 40.08% from 1954 to 2008) and a reduction of bare land (from 51.26% to 5.50% from 1954 to 2008) accounted for a large part of the change in land use. However, the land use changed little in the contrast catchment. The comparison of streamflow in the paired catchments showed that forestation reduced streamflow by 49.63% (or 6.5 mm) each year.

关键词： Surface water hydrology Climate variability/change Forests Land use/land cover change loess plateau of china

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Effects of Water-Collecting and -Retaining Techniques on Photosynthetic Rates, Yield, and Water Use Efficiency of Millet Grown in a Semiarid Region

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Journal of Integrative Agriculture 2012年第7期11卷 1119-1128页

作者： WEN Xiao-xia ZHANG De-qi LIAO Yun-cheng JIA Zhi-kuan JI Shu-qin College of Agronomy Northwest A&F University Yangling 712100 P.R.China Wheat Research Centre Henan Academy of Agricultural Sciences Zhengzhou 450002 P.R. China

Field experiments were conducted in 2003 and 2004 to study the effects of plastic ridges and furrow film mulching （plastic film on sowing, as well as plastic film on flat soil and hole sowing） and chemicals （a drought resistant agent and a water- retaining agent） on growth, photosynthetic rate, yield, and water use efficiency （WUE） of spring millet （Setaria italica L.）. The experimental results showed that water-collecting and -retaining techniques can effectively increase soil moisture content, the leaf photosynthetic rate and crop growth. Due to increased soil moisture under the plastic-covered ridge and furrow water-collecting in July and August, dry matter and plant height had a increase at the booting stage （late growth advantage）. However, the plastic-covered flat soil and hole sowing reduced soil evaporation during early growth, the increase of dry matter and plant height appeared at the seedling stage （early growth advantage）. Plastic-covered ridge and furrow sowing supplemented with chemical reagents had significant positive effects on water collection and soil moisture retention. Improvement of soil moisture resulted into the increase of the photosynthetic rate, dry matter accumulation yield and WUE. The water-collecting and -retaining techniques can improve WUE and enhance crop yield. Correlation analysis demonstrated that the photosynthetic rate under the water-collecting and -retaining techniques was significantly associated with the soil moisture, but had no significant relationship with leaf chlorophyll content. Plastic- covered ridge and furrow sowing supplemented with chemical reagents increased the yield and WUE by 114% and 8.16 kg ha-1 mm-1, respectively, compared with the control; while without the chemical reagents the yield and WUE were 95% and 7.42 kg ha-1 mm-1 higher, respectively, than those of the control.

关键词： water use efficiency loess plateau of china plastic film mulch drought-resistant agent water-retaining agent

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Long-Term Settlement Characterization of High-Filling Foundation in the Mountain Excavation and City Construction Area of the Yan’an New District,china

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Journal of Earth Science 2023年第6期34卷 1908-1915页

作者： Xiaokun Hou Shengwen Qi Yongtang Yu Jianguo Zheng Key Laboratory of Shale Gas and Geoengineering Institute of Geology and GeophysicsChinese Academy of SciencesBeijing 100029China Innovation Academy for Earth Sciences Chinese Academy of SciencesBeijing 100029China College of Earth and Planetary Sciences University of Chinese Academy of SciencesBeijing 100049China china United Northwest Institute for Engineering Design&Research Co. Ltd.Xi'an 710077China china Jikan Research Institute of Engineering Investigations and Design Co. Ltd.Xi'an 710021China

Mountain Excavation and City Construction(MECC)represents a prominent anthropogenic endeavor aimed at facilitating urban expansion in the loess plateau of *** is important to comprehend the long-term settlement behavior at MECC engineering sites to effectively assess the project’s success in reshaping landscapes and expanding urban *** this study,a typical MECC project,specifically the upstream area of the Liujiagou Valley within the new district of Yan’an City,is selected as a case study to investigate long-term settlement *** research involved conducting creep tests on soil samples with varying dry densities and moisture content and continuous in-situ monitoring of ground surface settlement at 17 specific ***,a numerical model was developed and calibrated using the in-situ monitoring data to predict the long-term *** findings reveal that an increase in soil dry density and a decrease in soil water content contribute to reduced ***,settlement primarily manifests within the filled areas,with greater soil thickness exacerbating settlement *** time,cumulative settlement exhibits a progressively diminishing rate of deformation until it attains a stable *** results provide insights for assessing the long-term stability of MECC projects,facilitating decision-making in future endeavors within this region.

关键词： loess plateau of china long-term settlement in-situ observation numerical analysis engineering geology

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Soil profile evolution following land-use change:implications for groundwater quantity and quality

Soil profile evolution following land-use change:implication...

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中国科学院地质与地球物理研究所2013年度（第13届）学术年会

作者： Tianming Huang Zhonghe Pang W.Mike Edmunds Key Laboratory of Engineering Geomechanics Institute of Geology and GeophysicsChinese Academy of Sciences Oxford University Centre for Water Research School of Geography and the Environment Oxford University

Soil and vadose zone profiles are used as an archive of changes in groundwater recharge and water quality following changes in land use in an area of the loess plateau of china.A typical rain-fed loess-terrace agriculture region in Hequan,Guyuan,is taken as an example,and multiple tracers(chloride mass balance,stable isotopes,tritium and water chemistry) are used to examine groundwater recharge mechanisms and to evaluate soil water chloride as an archive for recharge rate and water *** show that groundwater recharge beneath natural uncultivated grassland,used as a baseline,is about 94-100 mm year and that the time it takes for annual precipitation to reach water table through the thick unsaturated zone is from decades to hundreds of years(tritium free).This recharge rate is 2-3 orders of magnitude more than in the other semiarid areas with similar annual rainfall but with deep-rooted vegetation and relatively high *** of the water that eventually becomes recharge originally infiltrated in the summer *** conversion from native grassland to winter wheat has reduced gioundwater recharge by 42-50%(50-55 mm year for recharge),and the conversion from winter wheat to alfalfa resulted in a significant chloride accumulation in the upper soil zone,which terminated deep *** paper also evaluates the time lag between potential recharge and actual recharge to aquifer and between increase in solute concentration in soil moisture and mat in the aquifer following land-use change due to the deep unsaturated ***(?) 2012 John Wiley & Sons,Ltd.

关键词： groundwater recharge land-use change chloride mass balance loess plateau of china soil profile

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